Showing papers on "Zeatin published in 2021"

Melatonin improves the seed filling rate and endogenous hormonal mechanism in grains of summer maize.

Abstract: The unpredictable precipitation and water deficit conditions in semiarid regions significantly reduce the yield of summer maize. The exogenous application of plant growth regulators can be used as a strategy to enhance plant stress tolerance and improve the growth and yield of maize under semiarid conditions. Here, we studied the protective role of melatonin application on maize yield using grain filling rate and hormonal crosstalk in maize grains. In the first field experiment, seeds were soaked with melatonin at a concentration of 0 (SM0 ), 25 (SM1 ), 50 (SM2 ), and 75 μM (SM3 ) μM. In contrast, in the second experiment, melatonin was applied on the foliage at the ninth leaf stage at a concentration of 0 (FM0 ), 25 (FM1 ), 50 (FM2 ), and 75 (FM3 ) μM. Our findings showed that melatonin treatments as seed soaking significantly increased single seed weight, seed filling rate in superior, medium and inferior seeds by regulating the hormone levels compared to foliar application. Application of melatonin significantly increased the zeatin+zeatin riboside (Z+ZR), indole-3-acetic acid (IAA), and gibberellic acid (GA) contents. However, it significantly inhibited the contents of abscisic acid (ABA) during the seed filling period. The content of Z+ZR, IAA, and GA was positively correlated with the maximum seed filling rate, seed weight, and mean filling rate in middle, superior and lower seeds, while the ABA was negatively correlated. The ABA content in inferior seeds was positively correlated with the maximum and mean seed filling rate. In semiarid regions, melatonin treatment of SM2 and FM2 significantly increased the dry matter per plant, 100-grain weight, seed filling rate, IAA, Z+ZR, GA contents, ear characteristics, and maize yield.

Ethylene-Cytokinin Interaction Determines Early Defense Response of Wheat against Stagonospora nodorum Berk.

Abstract: Ethylene, salicylic acid (SA), and jasmonic acid are the key phytohormones involved in plant immunity, and other plant hormones have been demonstrated to interact with them. The classic phytohormone cytokinins are important participants of plant defense signaling. Crosstalk between ethylene and cytokinins has not been sufficiently studied as an aspect of plant immunity and is addressed in the present research. We compared expression of the genes responsible for hormonal metabolism and signaling in wheat cultivars differing in resistance to Stagonospora nodorum in response to their infection with fungal isolates, whose virulence depends on the presence of the necrotrophic effector SnTox3. Furthermore, we studied the action of the exogenous cytokinins, ethephon (2-chloroethylphosphonic acid, ethylene-releasing agent) and 1-methylcyclopropene (1-MCP, inhibitor of ethylene action) on infected plants. Wheat susceptibility was shown to develop due to suppression of reactive oxygen species production and decreased content of active cytokinins brought about by SnTox3-mediated activation of the ethylene signaling pathway. SnTox3 decreased cytokinin content most quickly by its activated glucosylation in an ethylene-dependent manner and, furthermore, by oxidative degradation and inhibition of biosynthesis in ethylene-dependent and ethylene-independent manners. Exogenous zeatin application enhanced wheat resistance against S. nodorum through inhibition of the ethylene signaling pathway and upregulation of SA-dependent genes. Thus, ethylene inhibited triggering of SA-dependent resistance mechanism, at least in part, by suppression of the cytokinin signaling pathway.

Hormonal changes with uniconazole trigger canopy apparent photosynthesis and grain filling in wheat crop in a semi-arid climate

Abstract: Phytohormones are important for the growth and development of plants. The objective of the experiment was to investigate the effect of foliar application of uniconazole (UCZ) at the four-leaf stage on hormone crosstalk and production of winter wheat. An experiment was carried out during 2015–2016 and 2016–2017 growth season in a semi-arid region, where UCZ at a concentration of 0 (CK, distilled water), 15 (FU15), 30 (FU30), and 45 (FU45) mg L−1 were sprayed on wheat crop at the four-leaf stage at a rate of 138.8 mL m−2. UCZ alters the endogenous hormone contents in flag leaves and in grains. UCZ inhibited gibberellic acid (GA) in flag leaves and in grains where the lower GA with UCZ improved the zeatin + zeatin riboside (Z + ZR) and abscisic acid (ABA) contents. The lower GA and higher Z + ZR and ABA contents with UCZ-treated plants improved the chlorophyll content and canopy apparent photosynthesis (CAP) as well as the grain-filling characteristics. The Z + ZR and ABA in flag leaves were positively correlated with chlorophyll content and CAP value while negatively with GA. Moreover, the Z + ZR and ABA were positively correlated with maximum grain weight, mean grain-filling rate, and maximum grain-filling rate, while negatively with GA level. Treatment FU30 significantly improved the chlorophyll content, CAP value, spike weight, grain-filling characteristics, and hormone contents of Z + ZR and ABA while it decreased the GA level. The hormone crosstalk with UCZ significantly increased the yield of wheat crop, where FU30 treatment performs better.

Plant Hormones and Volatiles Response to Temperature Stress in Sweet Corn ( Zea mays L.) Seedlings

Abstract: This work aims to emphasize on disclosing the regulative mechanism of sweet corn seedlings response to extreme temperature stress; transcriptomics and metabolomics for volatiles and plant hormones were integrated in this study. Results showed that low-temperature stress significantly impressed 20 volatiles; abscisic acid and salicylic acid accumulated, while auxin and jasmonic acid decreased. The regulatory patterns of vp14 and ABF for abscisic acid accumulation and signal transduction were elucidated in low-temperature stress. High-temperature stress influenced 31 volatiles and caused the reductions on zeatin, salicylic acid, jasmonic acid, and auxin. The up-regulation of an ARR-B gene emphasized its function on zeatin signal transduction under high-temperature stress. Correlations among gene modules, phytohormones, and volatiles were analyzed for building the regulative network of sweet corn seedlings under temperature stress. The attained result might build foundations for improving early development of sweet corn by biological intervention or genomic-level modulation.

Endophytic Strain Bacillus subtilis 26D Increases Levels of Phytohormones and Repairs Growth of Potato Plants after Colorado Potato Beetle Damage

Abstract: Plant damage caused by defoliating insects has a long-term negative effect on plant growth and productivity. Consequently, the restoration of plant growth after exposure to pathogens or pests is the main indicator of the effectiveness of the implemented defense reactions. A short-term Leptinotarsa decemlineata Say attack on potato tube-grown plantlets (Solanum tuberosum L.) led to a reduction of both the length and mass of the shoots in 9 days. The decrease of the content of phytohormones—indole-3-acetic acid (IAA), abscisic acid (ABA), zeatin and zeatin–riboside—in shoots of damaged potato plants was found. Endophytic strain Bacillus subtilis 26D (Cohn) is capable of secreting up to 83.6 ng/mL IAA and up to 150 ng/mL cytokinins into the culture medium. Inoculation of potato plants with cells of the B. subtilis 26D increases zeatin–riboside content in shoots and the mass of roots of undamaged plants, but does not influence content of IAA and ABA and growth of shoots. The presence of B. subtilis 26D in plant tissues promoted a rapid recovery of the growth rates of shoots, as well as the wet and dry mass of roots of plants after the pest attack, which we associate with the maintenance of a high level of IAA, ABA and cytokinins in their tissues.

Plant growth biostimulant activity of the green microalga Desmodesmus subspicatus

Abstract: The plant biostimulant activity of the green microalga Desmodesmus subspicatus was investigated, focusing on its potential application to organic crops. Different concentrations of D. subspicatus biomass suspensions were applied to tomato seedlings (Solanum lycopersicum) via a foliar spray. The treatments promoted root growth and foliar area, which increased when the suspension was applied at concentrations of 1 g L−1 and 0.4 g L−1, respectively. To elucidate the major constituents responsible for this potential activity, the biomass of D. subspicatus was submitted to aqueous extraction and dialysis (1 kDa cut-off), giving rise to the non-dialyzable fraction E (12.3%). Size-exclusion chromatography performed on fraction E using a Bio-Gel P-2 column yielded six subfractions. Gas chromatography-mass spectrometry (GC–MS) and nuclear magnetic resonance (NMR) analyses of the E subfractions revealed the presence of glycosides as major constituents (approx. 81%), including one acidic glycoside, [6-sulfo-α- D -quinovopyranosyl-(1→1)-glycerol], and two neutral galactosyl glycosides, [α- D -galactopyranosyl-(1→6)-β- D -galactopyranosyl-(1→1)-glycerol] and [β- D -galactopyranosyl-(1→1)-glycerol]. Ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS) analyses of fraction E resulted in the identification of the phytohormone zeatin (35 μg g−1). To evaluate the biostimulant potential of fraction E, different concentrations (0.5, 1.0, 1.5, and 2.0 g L−1) were tested for their effects on tomato seed germination, hypocotyl volume, and length. All tested concentrations induced increased hypocotyl lengths and volumes compared with standard treatment (water), at rates equivalent to those in response to a commercial product derived from Ascophyllum nodosum brown seaweed. These results indicated that the biomass suspension and aqueous extract of D. subspicatus showed plant growth biostimulant activity. Glycosides, together with zeatin, may play important roles in biostimulant activity.

Evaluation of High Salinity Tolerance in Pongamia pinnata (L.) Pierre by a Systematic Analysis of Hormone-Metabolic Network

Abstract: Salinity stress results in significant losses in plant productivity and loss of cultivable lands. Although Pongamia pinnata is reported to be a salt-tolerant semiarid biofuel tree, the adaptive mechanisms to saline environments are elusive. Despite a reduction in carbon exchange rate (CER), the unchanged relative water content provides no visible salinity induced symptoms in leaves of hydroponic cultivated Pongamia seedlings for 8 days. Our Na+ -specific fluorescence results demonstrated that there was an effective apoplastic sodium sequestration in the roots. Salinity stress significantly increased zeatin (~5.5-fold), and jasmonic acid (~3.8-fold) levels in leaves while zeatin (~2.5-fold) content increased in leaves as well as in roots of salt-treated plants. Metabolite analysis suggested that osmolytes such as myo-inositol and mannitol were enhanced by ~12-fold in leaves and roots of salt-treated plants. Additionally, leaves of Pongamia showed a significant enhancement in carbohydrate content, while fatty acids were accumulated in roots under salt stress condition. At the molecular level, salt stress enhanced the expression of genes related to transporters, including the Salt Overly Sensitive 2 gene (SOS2), SOS3, vacuolar-cation/proton exchanger, and vacuolar-proton/ATPase exclusively in leaves, whereas the Sodium Proton Exchanger1 (NHX1), Cation Calcium Exchanger (CCX), and Cyclic Nucleotide Gated Channel 5 (CNGC5) were up-regulated in roots. Antioxidant gene expression analysis clearly demonstrated that peroxidase levels were significantly enhanced by ~10-fold in leaves, while Catalase and Fe-superoxide Dismutase (Fe-SOD) genes were increased in roots under salt stress. The correlation interaction studies between phytohormones and metabolites revealed new insights into the molecular and metabolic adaptations that confer salinity tolerance to Pongamia.

Effects of culture medium and plant hormones in organogenesis in olive (CV. Kroneiki)

Abstract: Background: A long time has passed since the first experience of In Vitro propagation of olive, but the presence of very strong end dominance in the neoplasm stage, which cannot be controlled by various cytokinin treatments, has limited the possibility of propagation in vitro. Therefore, the aim of the present study was to evaluate the micro-propagation feasibility inside olive glasses of olive cultivar Kroneiki. Methods: For branching and rooting of lateral buds, the experiment was performed factorially in a completely randomized design with three replications. Branching factors include five types of culture media (MS, MS1/2, MSM, MSM1/2 and OM), two types of hormones (BAP and Zeatin), and three types of hormone concentrations (control, 0.5 and 1 mg/l) and there were three types of time periods. Rooting factors include five types of culture media (MS, MS1/2, MSM, MSM1/2 and OM), two types of hormone combinations (IBA and NAA), four types of hormone concentrations (control, combination of 0.2 with 0.5, combination 0.5 with 1 and a combination of 0.75 with 1.5 mg/l) and three types of time intervals. Analysis of variance was performed by Statistix10 software and the comparison of mean traits was performed using the least significant difference test. Results: The effect of culture medium, different hormones and also different concentrations of hormones used in the period, on the number of green leaves, number of yellow leaves, fresh weight and dry weight of seedlings as well as rooting were different (P <0.01). The highest length of branch (1.8 cm) was obtained in MSM culture medium with BAP hormone in the third week. The highest fresh weight (0.06 g), the highest dry weight (0.003 g) and the highest amount of green leaves (55.39%) were obtained from the treatment of MSM medium with 1 ppm of BAP hormone. The highest rooting rate (95.17%) was obtained from the treatment of MS1/2 medium with 1.5 ppm of BAP hormone and 0.75 ppm of NAA hormone in the third week. Conclusion: The most effective culture medium and hormone on branching were MSM culture medium with 1 ppm BAP hormone and on rooting, MS1 culture medium with 1.5 ppm BAP hormone and 0.75 ppm NAA hormone were obtained, respectively.

Optimizing micropropagation conditions for a recalcitrant ninebark (Physocarpus opulifolius L. maxim.) cultivar

Abstract: Ninebark is a very popular ornamental shrub. Micropropagation is an efficient method for mass production of uniform plant material. This study was designed to develop and optimize conditions at all phases of ninebark micropropagation. For the multiplication stage, the Murashige and Skoog (MS) medium at full concentration and pH 5.8 was chosen as the basal medium. Sorbitol proved a more effective carbohydrate source than fructose, with no adverse effects on shoot vitrification or the medium itself. The best shoot production, both in number and length, was on the medium enriched with 2 and 3 mg·L−1 zeatin. High numbers of shoots were also obtained in treatments with 1 mg·L−1 6-benzyladenine (BA) or 2 mg·L−1 meta-Topolin (mT) in the basal medium. BA was the most cost-effective cytokinin. There was a positive effect of the gibberellic acid on proliferation: the highest shoot number per explant was produced in the presence of 1 mg·L−1 GA3. No effect of the culture age (up to 20 subcultures) on the percentage of regenerating explants was evident, and the highest numbers of shoots were obtained between passages 10 and 17. For rooting, the MS medium at half strength was used. The best rooting was at 1 mg·L−1 IBA. Spraying the in vitro rooted cuttings with abscisic acid (ABA) favored plant acclimation to the ex vitro conditions. Ex vitro rooting, including the treatments with IBA and ABA, shortened the production time by approximately one third.

In vitro propagation of cambuci (Campomanesia phaea): An endangered exotic fruit and ornamental plant from Brazilian Atlantic Forest

Abstract: Cambuci (Campomanesia phaea) is a species from the Brazilian Atlantic Forest biome with a low propagation rate and is under risk of extinction. This plant has ornamental value, and its fruits have numerous nutraceutical and medicinal properties. The objective of the present study was to apply plant tissue culture techniques in its propagation. Seeds were germinated in vitro using MS and WPM medium at three pH values (5.8, 5.2, and 4.5). It was demonstrated that this species needs a reduced concentration of salts and acidic pH for its development. From in vitro twinned plants, three explant types (nodal segment, hypocotyl, and root) were evaluated under the action of the cytokinins BAP, zeatin, and kinetin at concentrations 0.0, 1.0, 2.0 and 3.0 mg L−1. The nodal segments inoculated on WPM medium containing 3% sucrose, 0.2% Phytagel®, 1.0 mg L−1 BAP at 4.5 pH showed the best formation of shoots, while the other treatments showed susceptibility to oxidation. Regenerated rooted plants showed a survival rate of 94.4% after acclimatization. Cambuci is a Brazilian forest biome species with extinction risk. This study demonstrated that a low salt concentration and acidic pH for the shoot formation under BAP 1.0 mg L−1.

Effect of medium composition, genotype and age of explant on the regeneration of hexaploid plants from endosperm culture of tetraploid kiwiberry (Actinidia arguta)

Abstract: Endosperm, an ephemeral and storage tissue, serves as a source of nutrition and protection during embryo development and germination. It can be used for the cultivation of polyploid plants in vitro. Here, results of plant regeneration and acclimatization from the endosperm-derived calli of four cultivars of Actinidia arguta has been presented. Seeds excised from fresh fruit and dry seeds stored for one year served as the sources of endosperm explants of selected tetraploid cultivars of A. arguta. Callus Induction Medium (CIM; containing 0.25, 0.5, or 1 mg/l of TDZ) and Actinidia Endosperm Medium (AEM; containing 2 mg/l of 2,4-D and 5 mg/l of kinetin) were used to study the organogenic responses of the calli. On AEM, the source of explant did not significantly affect the rate of callus induction for any of the tested cultivars; no organogenic events were observed. In contrast, on CIM both the source of explants and the cultivar origin caused significant differences in callus formation and subsequent organogenic events. Histological and ultrastructural analyses revealed the adventitious nature of shoot bud formation on these media. The most efficient elongation of shoot buds was achieved after transferring organogenic calli with adventitious shoot buds to a medium supplemented with zeatin or meta-topolin. Robust root induction with minimal basal callus formation occurred on the medium with indole-3-acetic acid. Flow cytometric analysis revealed that the nuclear DNA content in the leaves of some regenerants was approximately 50 % higher (4.5 pg/2C) than that in leaves from the tetraploid seedlings (3.1 pg/2C),which confirmed that those regenerants originated from the endosperm. The regeneration of such hexaploid plants was more efficient when endosperm from fresh seeds served as an explant; therefore, fresh rather than dry seeds are recommended for endosperm-derived plant production. The hexaploid plants of A. arguta can serve as an important source of breeding material. This study reveals that the genotype, thidiazuron, zeatine, meta-topolin, and age of explants affect the induction of endosperm-derived callus and subsequent hexaploid plant regeneration from tetraploid kiwiberry.

Molecular mechanism of lateral bud differentiation of Pinus massoniana based on high-throughput sequencing.

Abstract: Knot-free timber cultivation is an important goal of forest breeding, and lateral shoots affect yield and stem shape of tree. The purpose of this study was to analyze the molecular mechanism of lateral bud development by removing the apical dominance of Pinus massoniana young seedlings through transcriptome sequencing and identify key genes involved in lateral bud development. We analyzed hormone contents and transcriptome data for removal of apical dominant of lateral buds as well as apical and lateral buds of normal development ones. Data were analyzed using an comprehensive approach of pathway- and gene-set enrichment analysis, Mapman visualization tool, and gene expression analysis. Our results showed that the contents of auxin (IAA), Zea and strigolactone (SL) in lateral buds significantly increased after removal of apical dominance, while abscisic acid (ABA) decreased. Gibberellin (GA) metabolism, cytokinin (CK), jasmonic acid, zeatin pathway-related genes positively regulated lateral bud development, ABA metabolism-related genes basically negatively regulated lateral bud differentiation, auxin, ethylene, SLs were positive and negative regulation, while only A small number of genes of SA and BRASSINOSTEROID, such as TGA and TCH4, were involved in lateral bud development. In addition, it was speculated that transcription factors such as WRKY, TCP, MYB, HSP, AuxIAA, and AP2 played important roles in the development of lateral buds. In summary, our results provided a better understanding of lateral bud differentiation and lateral shoot formation of P. massoniana from transcriptome level. It provided a basis for molecular characteristics of side branch formation of other timber forests, and contributed to knot-free breeding of forest trees.

Shoot Multiplication and Callus Induction of Labisia pumila var. alata as Influenced by Different Plant Growth Regulators Treatments and Its Polyphenolic Activities Compared with the Wild Plant.

Abstract: This study aims to investigate whether the in vitro-cultured L. pumila var. alata has higher antioxidant activity than its wild plant. An 8-week-old L. pumila var. alata nodal segment and leaf explants were cultured onto Murashige and Skoog (MS) medium supplemented with various cytokinins (zeatin, kinetin, and 6-benzylaminopurine (BAP)) for shoot multiplication and auxins (2,4-dichlorophenoxyacetic acid (2,4-D) and picloram) for callus induction, respectively. The results showed that 2 mg/L zeatin produced the optimal results for shoot and leaf development, and 0.5 mg/L 2,4-D produced the highest callus induction results (60%). After this, 0.5 mg/L 2,4-D was combined with 0.25 mg/L cytokinins and supplemented to the MS medium. The optimal results for callus induction (100%) with yellowish to greenish and compact texture were obtained using 0.5 mg/L 2,4-D combined with 0.25 mg/L zeatin. Leaves obtained from in vitro plantlets and wild plants as well as callus were extracted and analyzed for their antioxidant activities (DPPH and FRAP methods) and polyphenolic properties (total flavonoid and total phenolic content). When compared with leaf extracts of in vitro plantlets and wild plants of L. pumila var. alata, the callus extract displayed significantly higher antioxidant activities and total phenolic and flavonoid content. Hence, callus culture potentially can be adapted for antioxidant and polyphenolic production to satisfy pharmaceutical and nutraceutical needs while conserving wild L. pumila var. alata.

Evaluation of genetic stability in olive callus-induced and meristem-induced shoots using flow cytometry and amplified fragment length polymorphism techniques

Abstract: In vitro culture of olive, as an economically valuable tree, has fundamentally a genotype-dependant low micropropagation rate which needs to be improved in already established and newly released cultivars. Various plant tissue culture media, planting systems and growth factors were evaluated in two promissing Iranian olive cultivars ˈAminˈ and ˈMeshkatˈ and the commercial Spanish cultivar ˈArbequinaˈ. The results showed that cultivars have their specific optimal media, i.e. ˈAminˈ in the MS with 4 mg/L zeatin, ˈArbequinaˈ in the OM with 1 mg/L zeatin, and ˈMeshkatˈ in the OM and MS with 2 mg/L zeatin, which produced significantly a higher number of axillary shoots than other media. The results also indicated a significant improvement in the growth indices of ˈAminˈ (number of axillary shoots) when cultured using periodical mini bioreactor (PMB) in the VS medium. In comparison with VS, OM did not reveal any significant differences when both culturing systems (PMB and semi-solid media (SSM)) were used. Regarding the effect of carbon source and light intensity, mannitol and 2000 cd sr m−2 greatly enhanced ˈArbequinaˈ growth indices (main shoot length and growth quality). The results of genetic stability of callus induced shoots (CIS) and meristem induced shoots (MIS) revealed that 2C DNA value assessed by partec flow cytometery (FCM) had 0.01, 0.03 and 0.08 pg discrepencies in ˈAminˈ, ˈArbequinaˈ and ˈMeshkatˈ, repectively. The Amplified Fragment Length Polymorphism (AFLP) results also indicated that the cultivars were classified regardless of the micropropagation origin (CIS or MIS), except for ˈArbequinaˈ. The AFLP findings showed that ˈArbequinaˈ had the highest dispersal (7–38%) in CIS and MIS, while the Iranian cultivar of ˈMeshkatˈ (5–9%) had the highest stability. This study indicated the importance of in vitro growth parameters for improving the micropropagation indices of olive cultivars. It showed that optimized protocols (OM, PMB, zeatin, mannitol and 2000 cd sr m−2) co-produced larger calli resulting in indirect organogenesis. Based on FCM and AFLP analysis, it can be concluded that true-to-typeness of micropropagated olive was cultivar-dependent.

Foliar Thidiazuron Promotes the Growth of Axillary Buds in Strawberry

Abstract: Strawberry (Fragaria × ananassa Duch.) can be easily propagated with daughter plants or through crown division, which are developed from the axillary bud at the axils of leaves. This study was conducted to investigate the effects of different cytokinins, auxins, and their combinations on the axillary bud growth in strawberry. Four cytokinins (6-benzyladenine, kinetin, zeatin, and thidiazuron (TDZ)) and three auxins (indole-3-acetic acid, indole-3-butyric acid, and naphthaleneacetic acid) at a concentration of 50 mg·L−1 were sprayed on the leaves three times in 10-day intervals. The expression levels of cytokinin, auxin, and meristem-related genes in the crowns were also investigated. The results showed that TDZ was the most effective hormone for the axillary bud growth, and also promoted plant growth. However, chlorophyll, soluble sugar, and starch contents in the leaves were lower after TDZ. TDZ activated the cytokinin signal transduction pathway, while repressing the auxin synthesis genes. Several meristem-related transcription factors were upregulated, which might be essential for the growth of the axillary buds. These results suggested that TDZ can improve the cultivation of strawberry, while further research is needed to explain the effect on phytochemistry.

Micropropagation through indirect organogenesis in Solanum capsicoides All., and assessment of clonal fidelity using ISSR markers

Abstract: Solanum capsicoides All., is an important medicinal plant which is used as a source of ‘Kantakari’ (medicine for phlegm disorders) in India. The restricted distribution of the plant in Kerala along with its overexploitation necessitates the development of a protocol for in vitro propagation of S. capsicoides. The present study reports the effects of four different cytokinins (2 isopentenyl adenine (2iP), benzyl adenine (BAP), kinetin (KIN), and zeatin (ZEA)) in combination with indole 3-butyric acid (IBA) on indirect organogenesis of S. capsicoides from in vitro grown seedling explants such as cotyledon, shoot tip, and hypocotyl. Maximum shoot development was observed from cotyledon explants inoculated on MS medium supplemented with 2.46 μM IBA and 4.56 μM ZEA. An average of 17 ± 0.5 shoots per cotyledon with an average length of 0.53 ± 0.03 cm was observed. After subculture, an average of 20 ± 1 shoots was observed in cotyledon explants inoculated on Murashige and Skoog medium supplemented with 2.46 μM IBA and 6.84 μM ZEA. Clonal fidelity of regenerated plants was confirmed using DNA based molecular marker, intersimple sequence repeat (ISSR). Clonal fidelity test revealed 0% polymorphism and the PIC value 0 which indicate no diversity from seed-borne plants. The protocol thus developed can be used for rapid multiplication and conservation of S. capsicoides.

Half-high blueberry plants from bioreactor culture display elevated levels of DNA methylation polymorphism

Abstract: Blueberry (Vaccinium spp. L.) plants exhibit high potential of regeneration via adventitious shoot formation on a semi-solid medium followed by shoot elongation in a liquid medium under bioreactor systems. To find out whether DNA methylation plays a role during shoot elongation, we compared DNA methylation level in the regenerants of two in vitro-grown half-high blueberry (V. corymbosum L. × V. angustifolium Ait.) cultivars Patriot and Chippewa on a semi-solid medium (SSM) in glass bottles and in a liquid medium in temporary immersion bioreactors (TIB), via methylation-sensitive amplification polymorphism (MSAP) technique. The SSM was separately fortified with various combinations of two plant growth regulators, zeatin and thidiazuron for shoot regeneration but elongation was carried out using the same medium under both SSM and TIB systems with only zeatin. Zeatin at 9.2 µM produced the maximum shoots in SSM and TIB for both cultivars, which varied from 30 to 33 in SSM and from 28 to 29 in TIB for Patriot and Chippewa, respectively. However, shoots proliferated in TIB were more vigorous. Noticeable changes in the methylation profiles were detected using MSAP in the regenerants grown in each type of culture system. The TIB system exhibited a significant increase in total methylation percentage (47–50%) in comparison to SSM (25–32%) in both cultivars. Similarly, the plants regenerated from TIB system were more polymorphic than those from SSM system. We describe here the effects of culture in vitro on DNA methylation that induced during the process of shoot elongation in two half-high blueberry cultivars. In vitro shoot culture was achieved in half-high blueberry cultivars using a semi-solid and a liquid medium; plantlets developed from liquid medium showed higher level of DNA methylation alterations.

Chitosan Oligosaccharides Stimulate the Efficacy of Somatic Embryogenesis in Different Genotypes of the Liriodendron Hybrid

Abstract: Liriodendron hybrid (L. chinense × L. tulipifera), an essential medium-sized tree generally famous for its timber, is also used as an ornamental and greenery tool in many places around the world. The Liriodendron hybrid (L. hybrid) tree goes through many hurdles to achieve its maximum strength and vigor, such as loss of habitat, vast genetic variation, and low seed setting rate. The establishment of an effective and well-organized somatic embryogenesis (S.E.) system could be used to overcome these obstacles, rather than the old-fashioned seed culture and organogenesis. This study is based on the impact of chitosan oligosaccharide (COS) and its role in the induction of S.E. on the callus of four genotypes of the L. hybrid. The optimal concentration of COS could enhance the momentum and effectiveness in S.E.’s mechanism, which further improves the growth rate of the L. hybrid tree’s plantlets. This study shows that COS has a prominent role in endogenous hormones like indole acetic acid (IAA), zeatin (Z.T.), and gibberellic acid (GA3). Furthermore, COS improves the growth development, growth speed, as well as the development situation of plant germination ability. COS can also regulate branch development and root growth, which could be linked to the antagonistic effect on growth factors to some extent or by affecting auxin synthesis and polar transport.

Determination of cytogenetic and epigenetic effects of manganese and copper on Zea mays L.

Abstract: Heavy metal accumulation and its possible effects are prominent problem for not only human health but also for the environment and plant systems due to that heavy metals are non-biodegradable. In this research, it was aimed to examine the impacts of heavy metals on toxicity and genotoxicity in maize. Seeds of corn were subjected to various concentrations of MnSO4 and CuSO4 for determining their effects on DNA methylation, DNA damage levels, protein and phytohormone alterations. The results revealed that an increase in copper and manganese concentrations causes decrease in soluble protein levels, genomic template stability (GTS) and mitotic index but causes an increase in RAPD profile alterations and DNA hypermethylation. Additionally, HPLC analyses show that CuSO4 and MnSO4 contamination reduces growth-promoting hormones, like gibberellic acid (GA), zeatin (ZA) and indole acetic acid (IAA), and increases the abscisic acid (ABA). This study obviously indicated that CuSO4 and MnSO4 have epigenetic and genotoxic effects. A decrease in the phytohormone level (ZA, GA, and IAA) and an increase in the ABA level under CuSO4 and MnSO4 are thought to be a part of the defense system of maize to struggle with stress.

Effect of seed priming with zeatin on Secale cereale L. growth and cytokinins homeostasis under hyperthermia

Abstract: The rise in temperature during autumn is one of the most serious negative factors for winter rye (Secale cereale L.), which leads to wilting, plant damage by fungal diseases and yield losses. The a...

Molecular profiling of the Mahanarva spectabilis salivary glands and phytohormonal response of elephant grass

Abstract: Signal perception in plants is determinant to trigger specific physiological changes that confer resistance during the early stages of the insect attack. Thus, molecular characterization of both insect effectors and plant hormonal regulators are essential in developing forage grasses resistant to infestation by spittlebug Mahanarva spectabilis. We evaluated the presence of effectors in the salivary glands of M. spectabilis that could enable the infestation of elephant grass (Pennisetum purpureum). The presence of an NTPDase-like enzyme was confirmed, and higher activity was observed in females that hydrolyzed ADP. High levels of long chain fatty acids, such as octadecanoid acid (19.5%), prostaglandin A2 (4.7%), eicosanoid acid and the phytohormone salicylic acid (~4.0 μg/g) were also detected in the salivary glands. After 24 h of infestation, the phytohormone profiles were altered in leaves damaged by M. spectabilis, suggesting that the insect effectors modulate the plant response. Our results suggest that the plant response modulation may be the result of crosstalk between the salicylic acid, jasmonic acid, abscisic acid and zeatin pathways, induced by molecules from the salivary glands. This shows that the spittlebugs can interfere with jasmonic acid and zeatin accumulation in elephant grass plants.

Comparative assessment of The Effect of Moringa oleifera Leaf Extract (MLE) and Zeatin on invitro Regeneration Response of Pogostemon cablin Bud Explants

Abstract: Patchouli is one of the essential oil-producing plants which is commonly found in Indonesia, but the productivity tends to decline. Tissue culture technology is one alternative to increase patchouli plant productivity. Tissue culture requires growth regulators in order for the plants to grow optimally. Moringa plants have the potential as a source of growth regulators for tissue culture because Moringa leaves contain the zeatin hormone. Therefore, a comparison test of various concentrations of the zeatin and the moringa leaf extract is needed to determine whether the Moringa leaf extract can be an alternative to the zeatin hormone. This study aimed to investigate the effect of Moringa leaf extract on the growth of patchouli bud explants. The study employed a complete random design (CRD) with the treatment of concentrations of Moringa leaf extract in MS media. Moringa leaf extract was given at 30 grams/L, 40 grams/L, and 50 grams/L, respectively. Meanwhile, the zeatin hormone was given at a concentration of 1.5 ppm, 2 ppm, and 2.5 ppm. Each treatment was repeated four times. Moringa leaves were extracted by maceration method, and patchouli explants were obtained from the 3rd sub-culture of patchouli shoots. From the research results, it can be concluded that (1) the use of Moringa leaf extract can improve the growth of patchouli explants, and (2) the use of 40 grams/L of Moringa leaf extract can be an alternative to substitute the use of 1.5 ppm zeatin hormone.